DISSECTING MANUAL. 



below this the posterior edge presents a marked groove. The 

 inner surface of the inferior ramus is smooth and its lower 

 edge tends to be everted. [217] 



Pubis. This is the lower and front part and consists of a 

 body and two rami. The body has two surfaces, inner (pos- 

 terior) and outer (anterior), and two borders. The inner 

 border presents an oval facet (symphysis). The thick upper 

 border (crest) ends externally in a process (spine), and joins 

 the inner border internally, forming the angle. The superior 

 (ascending or horizontal) ramus runs upward and outward 

 from the body and forms one-fifth of the acetabulum. It has 

 three surfaces, viz.: internal (posterior), which is smooth and 

 concave, with a sharp inferior border; antero-inferior, which 

 roofs over a groove (obturator) running downward and for- 

 ward between the lower borders of the antero-superior and 

 internal surfaces; and antero-superior. The latter surface is 

 triangular with its apex at the spine, while its base lies at the 

 ileo-pectineal eminence above and the edge of the cotyloid 

 notch below; the anterior border is a ridge (obturator crest) 

 running from the spine to the cotyloid notch, while the postero- 

 superior border prolongs the ileo-pectineal line to the spine. 

 The inferior (descending) ramus is flattened and runs down- 

 ward and outward from the body to join the ischial ascending 

 ramus. It has two surfaces, external and internal, and two bor- 

 ders, upper and lower; the latter is everted. [218] 



Acetabulum (cotyloid cavity). This nearly circular hollow 

 for the head of the femur looks downward, outward, and for- 

 ward. A prominent margin surrounds it except opposite the 

 obturator foramen, where it is deficient (cotyloid notch) . The 

 floor has a horseshoe-shaped articular surface, which encloses 

 a rather circular rough area (fossa acetabuli) continuous with 

 the floor of the cotyloid notch. Thyroid (obturator) foramen : 

 This lies between the pubis and ischium; it varies in shape 

 from oval to triangular. Its margins are sharp except where 

 the obturator groove channels the pubic superior ramus. 



[186] 



